There is an increase in demand for high performance, non-hazardous and environmentally safe lubricant additives for greases, oils, metal working fluids, and compositions such as mineral oils and aqueous based synthetic fluids used in metal forming operations such as wire drawing and metal forging. In the case of greases and oils which have incidental contact with food, very few lubricant additives are available which satisfy both the required non-toxic properties and the performance needed by modern machinery. In formulating metal working fluids for cutting, grinding, broaching, tapping, and the like, certain sulfur-, chlorine-, and phosphorus-containing compounds are generally used as the extreme pressure and antiwear additives. However, the presence of chlorine-containing compounds may result in certain difficulties including corrosion and disposal problems. In metal forming operations like metal drawing and forging, molybdenum disulfide and other metal sulfides are commonly employed. Subsequent treatment of the work pieces is usually required to remove the residual sulfides by means of an acid pickling bath or mechanical descaling. Disposal of the sludges from acid pickling bath may present environmental hazards and can be quite expensive due to the presence of heavy metals.
Accordingly, one object of this invention is to provide a lubricant containing synergistic additives that impart both extreme pressure and antiwear properties to the base lubricant. Another object is to provide lubricants with the synergistic additives that are non-hazardous, environmentally safe, and easily disposed of after use.